Best Gas Tankless Water Heaters: Top Picks and Buying Guide

The best gas tankless water heater will be an excellent investment in every household. This is going to provide you with instantaneous hot water. There is no need to wait long as water will be instantly hot as it flows out of the shower or faucet. The costs of operating such a heater can also prove to be practical in the long run, especially if you choose the right product.

If you are having difficulty deciding which gas tankless water heater can provide the best bang for the buck, read on and find out. We will start by discussing the essential factors to consider when shopping for alternatives and will have a run-down of three of the products that should definitely be included in your list.

Best Gas Tankless Water


Top Picks for the Best Gas Tankless Water Heater

The table below provides a quick look at the three products that are worth your money. After the table, we will have a more in-depth discussion of what you can expect in each product, including its pros and cons.

Product namePriceOur Rating
Rheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water Heater$$$9.5/10
Takagi T-D2-IN-NG Indoor Tankless Water Heater, Natural Gas$$9/10
Rinnai V65IN 6.6 GPM Indoor Low NOx Tankless Natural Gas Water Heater$9.8/10

Rheem RTGH-95DVLN Tankless Water Heater


Rheem RTGH-95DVLN 9.5 GPM best gas tankless water heater


With a flow rate of 9.5 gallons per minute, this is an excellent heater for a house with several bathrooms. You will not have any problem even if you use two showers simultaneously. You can be sure that there will be a supply of hot water.

The heat condensing body is one of the noteworthy features that you will find in this product. The body is made of high-quality stainless steel, which is not easily prone to external factors that could speed up wear and tear, such as in the case of rust and corrosion.

It is also a good thing that the heater comes with EZ-Link wire. To put it simply, the latter will allow users to connect two different water heaters and make them function as one, which will result in an even better heating performance.

Do you live in a place with a high altitude? This heater will be perfect for you. Based on the technical details from the manufacturer, it is good for up to 9,840 feet of elevation.

Lastly, the manufacturer is offering an extensive 12-year warranty, which demonstrates their belief in the superior quality of their product. Nonetheless, take note that this warranty is for the heat exchanger only. The component parts are covered for five years while labor is free one year from the date of purchase.


  • High-Quality Construction: The durability of this product is one thing that will give this an edge over its competitors. It has a rugged construction, providing you with the assurance that it can offer longevity in the absence of compromising its heating performance.
  • Energy-Efficient: There is also no need to worry about the consumption of gas of this water heater. Even if it is used daily and in a large house, you can be confident of its efficiency, allowing you to enjoy long-term savings.
  • Abundant Safety Features: If you want to have peace of mind, you will have another good reason to choose this heater. For instance, it comes with freeze protection, which comes handy if you are living in a place where it is often chilly.
  • Flexible Venting: The venting of this water heater has also been praised by many because of its flexibility. As the owner, you will have the freedom to choose whether you would like to have it vented indoors or outdoors.


  • Expensive Price: This is not for you if you are looking for a budget-friendly water heater. The steep price of this product is one thing that can easily discourage many people. Nonetheless, if you read reviews and take a close look at its features, it will be easy for you to understand why this is quite an expensive product.
  • Not for Smaller Households: If you have a small house, better stay away from this water heater. It is designed with large spaces in mind. It may be too much for some people, especially if you only are one to four in a house.

Buy this water heater if you have the budget and if you are living in a large house that needs hot water on demand.

Takagi T-KJR2-IN-NG Gas Tankless Water Heater

Takagi T-KJr2-IN-NG best gas tankless water heater


This gas tankless water heater has a maximum BTU of 140,000 and minimum BTU of 19,500. Meanwhile, the flow rate is 6.6 GPM. Based on its technical features, you should know that this is ideal only for a small household and for light use. For warmer climates, it can heat two showers. For colder climate, on the other hand, it can heat only one shower.

For ease of controlling the heater, there is a remote that is included. This makes it possible to control its functions even when you are at a distance.

When it comes to safety features, there are also many things that will make this exceptional despite its practical price. It has protection from overheating, freezing, and surge. There are also diagnostic codes that can be displayed, which will make troubleshooting a snap for you.

Similar to other Takagi heaters, this model also comes with a temperature check, which will make sure of the stability of heat when the unit is used.

Lastly, to be easily convinced that this can provide the best bang for the buck, you must know that its heat exchanger is covered by a 15-year warranty and other parts are covered for 5 years, provided that the heater is used only in a residence.


  • Reasonable Price: This is definitely not the cheapest water heater that you can find. Nonetheless, the price is still practical compared to its leading competitors and considering the fact that it can deliver exceptional performance.
  • User-Friendly: There is no need to have an advanced technical knowledge to figure out how to use this water heater. Operating the unit will be a snap, especially because the manufacturer provides comprehensive instructions on how you will be able to do so.
  • Long Functional Life: Based on the information from the manufacturer, on average, the unit will last up to ten years. Of course, the service life will depend on the extent of use of the heater, as well as care and maintenance.
  • Low Emissions: This is one thing that you can also find from the two other products that are mentioned in this buying guide. Even if it is powered by gas, it is good to know that it produces minimal emissions.
  • Performs at Different Altitudes: This benefit is made possible by the advanced switches that are incorporated in the unit. By pushing the switch, you can make the heater deliver optimal functionality depending on the specified altitude.


  • Limited Heating Capacity: If you have a big house and if you need hot water in more than two bathrooms, you might want to consider looking at the other possibilities. Given its affordable price, it is easy to understand that the heating capacity is also limited.
  • Professional Installation: This is one thing that is common in many gas water heaters. Compared to their electric counterparts, the installation will be more complicated, and hence, it will be best handled by someone who has the expertise in doing so.

This is the heater that you should purchase if you are looking for one that is easy on the wallet and that is ideal only for light use.

Rinnai V65IN Tankless Gas Water Heater


Rinnai V65IN 6.5 best gas tankless water heater


With .82 energy factor rating and an Energy Star certification, this will be excellent in terms of energy efficiency. It will consume minimal natural gas while providing you with the assurance that it will heat water as desired.

Feature-wise, there are many things worth noting. For instance, there is a temperature lock to make sure that the heat of the water will remain consistent. There is also enhanced scale detection to prolong the functional life of the heater and to lessen wear and tear. More so, there is also protection from frost or freezing.

If you are looking for a water heater that can be used for an RV or trailer, this will also prove to be an exceptional pick. It has Certified Installation in Manufactured Homes, which is why it is legal for mobile use.

Troubleshooting this product will not require too much of an effort on your end. There is an error code indicator, allowing you to quickly diagnose a problem and determine the best way on how you can have it fixed.

Lastly, the warranty that is offered by the manufacturer is ten years for the heat exchanger, five years for parts, and one year for labor. As with other products, be sure to follow the terms and conditions specified by the manufacturer to be eligible for the warranty.


  • Sleek Design: Even if this is meant only for indoor installation, there should be no problem. This is because of its compact size, which means that its installation will not require a generous amount of space.
  • Environment-Friendly: The main reason for this is the fact that it generates minimal emissions, similar to the two other products that are reviewed in this post. To add, it also consumes minimal energy or gas as it heats water.
  • Safe Operations: This is important if you want to have peace of mind. There is an automatic shut-down feature if it is not cleaned properly. There is also a built-in capacity to detect a leak.
  • Long-Lasting: This is also a good choice if you are looking for longevity. The quality of the materials used is commendable, making the heater withstand the test of time, even if it is frequently used.
  • Flexible Temperature Range: This is one of the reasons why many people gave it a high rating when it comes to versatility. You will be able to customize the temperature settings from 98 to 140 degrees.


  • Indoor Installation Only: As it has been stated by the manufacturer, this model is good only to be installed indoors. It would have been better if you can also install it outdoors for flexibility and space-efficiency, especially if you have a small space.
  • Slow Response: Compared to smaller gas water heaters, the response of this model can be quite slower, which can take up to thirty seconds before the water heats. This can be attributed to its size and heating capacity.

This is a good choice if you are looking for a mid-sized water heater that is ideal for an average household.

Gas Tankless Water Heater Buying Guide

gas tankless water heater

Before we proceed further with the rest of the discussions in this post, let us first look at some of the most important factors that you have to take into account. Especially if it is your first time to buy such a product, you need to consider a variety of things to be assured of making the right choice.

Know the Right Size

size best gas tankless water heaterTo make it easier to differentiate the possibilities, one of the first things that need to be done is to learn about the size of the water heater that you have. Many manufacturers will offer a free online calculator that will help you to compute which heater is best suited for the size of your home.

If you buy a water heater that is too small, you will suffer from lack of hot water. On the other hand, if it is too big for the household, you will end up wasting gas or money.

You need to think about how many showers and sinks you have at home and if they need hot water. Think about their flow rate, which is expressed as gallons per minute. Add all of these to determine the minimum capacity of the heater that you have to purchase.

Type of Fuel

Since the tankless water heater is a gas type, it obviously needs fuel to function. This will be its source of power. In this case, there are two common choices – propane or natural gas.

Price is obviously one of the first things that you have to think about. In this case, natural gas is the cheaper option compared to propane. The cost of natural gas is measured per cubic foot, while it is expressed per gallon in the case of propane gas. Nonetheless, keep in mind that there are other factors that will come into play, such as the size of your home and the supplier of the gas.

The two fuel types are also different in terms of their form and portability. Natural gas is delivered to your home via a pipeline, so you have to check if it is available in your area. Propane gas, on the other hand, is more portable as it can be sold in canisters and delivered in your footsteps.

Location where the Heater will be Used

Where do you live? Do you live in an area that is cold or warm? This is important as this will also help to determine which gas tankless water heater will be most appropriate for your needs. Take note that if you are from a place where it is extremely cold, the heater will need to exert more effort to heat your water.

The altitude of your home will also be an important factor. Look at the technical specifications and see if it is right for your place. If you live in a place with a high altitude, you might need to settle for a more powerful water heater.

Installation Requirements

installation gas tankless water heaterOne of the most important concerning installation will be the costs that are involved. From retrofitting to venting, there are many things that will require spending. Even if there is an existing gas line, some modifications may be needed depending on where you intend to position the water heater.

Aside from costs, the difficulty of the installation is also an important factor. To be sure, however, you need to leave it to the hands of the pros. Do not attempt to complete the assembly on your own, especially if you do not have prior knowledge and experience. You might end up compromising its functionality and safety.

To add, the unit must also be inclusive of the hardware that will be needed to install the unit. It is a hassle if you will be receiving a box that has missing screws or bolts. The manufacturer must also provide a comprehensive instruction manual.

Safety Features

As it will be discussed in the next section of this post, safety is an important factor in a gas tankless water heater. You need to take a look at the features to guarantee that it will operate in the safest manner possible. It should have certifications and should have passed a stringent quality control test.

Feature-wise, the water heater needs to have combustion technology and flame failure protection. It must use only components with the highest quality. It should also have protection from freezing, especially if you live in an area where it is extremely cold.

Technical Specifications

You also need to have the time to look at the technical details of the product and understand what it means. These things are important because they can be indicative of the performance of the heater and their heating capabilities. That being said, here are some of the most important things that should be looked at:

Energy Factor: Technically speaking, this refers to the amount of hot water that will be produced by the heater per unit of fuel that will be used within a day. A higher energy factor rating would mean that the unit is more energy-efficient, and hence, it uses less gas to heat water.

Gallons Per Minute: Expressed as GPM, this will be indicative of the capacity of the heater. If you live in a small household, 4 gallons per minute will be enough. If you live in a large place, on the other hand, the minimum should be at least 7 gallons per minute.

British Thermal Unit: Expressed as BTU, this is in reference to the amount of gas that will be required for heating water in the tank for an hour. The higher the BTU, the more powerful is the heating ability of the product.

Low Nox: As much as possible, you have to choose a gas tankless water heater that is labeled as a Low Nox model, which means that it produces low emissions, and hence, it is good for the environment. They are equipped with a special vent pipe that allows combustion gases to be directed to the inner vent.

Overall Construction

This is one more thing that will help you to determine the overall quality of the unit, especially its durability. It should be made from high-quality materials that must withstand the test of time. All of its components should also demonstrate superior quality, which means that they will not be easily prone to wear and tear.

The overall construction is important not only in terms of durability, but also when it comes to safety. For the unit to be less prone to fire and other safety hazards, it should be constructed with the use of exceptional materials.

Warranty Coverage

This is an important consideration if you want to have peace of mind. In the case of most models, they will have a warranty that lasts for one year. A better option would be those with a warranty that lasts longer, perhaps up to 15 years or even a lifetime.

The length and coverage of the warranty can be different depending on the terms and conditions from the manufacturer. Usually, the heat exchanger is covered for a longer period and the warranty is shorter for the other parts and labor.

Be sure to read the terms of the warranty. If the problem is a result of negligence or wrong use of the heater, expect that the warranty will not be honored by the manufacturer or the seller.

Safety Tips for Using a Gas Tankless Water Heater

safety gas tankless water heaterEspecially if you are careless in the use of your gas tankless water heater, it is inevitable that you will be confronted with an unfortunate situation. Among others, one of the most common would be bursting and an explosion of the heater. This can start a fire and put you at risk. To avoid these things, this section discusses some of the best safety tips to keep in mind.

Make sure to set the right temperature of the water heater. Refer to the manual from the manufacturer to know the maximum heat settings. If it is too hot, there is a higher likelihood that it will be prone to problems, such as a fire. Scalding and burns are common when the water is too hot.

Be careful when using anything that is flammable near the water heater. Since it is powered by gas, it can easily start a fire.

Follow the installation guidelines from the manufacturer. You should do it based on what is recommended by the manufacturer. As much as possible, ask a pro to do the installation to lessen the risks that are associated with its use.

Lastly, and perhaps most importantly, the water heater needs a regular inspection to spot any problem early on and to prevent it from getting worse. When there are repairs needed, work only with licensed technicians who have the expertise to deal with the problem in the best way possible.

Care and Maintenance for Gas Tankless Water Heater

maintenance gas tankless water heaterTo ensure safety and peak performance of the gas tankless water heater throughout its functional life, you need to exert effort in maintaining the unit at its best. More often than not, this will require minimal effort on your end, yet it can make a huge difference in the performance of your water heater.

Similar to what has been recommended above, you need to inspect the unit regularly. If there are damages or dents, this should be seen as a sign that there is a problem. To add, if there are weird sounds coming from the heater, this can also be an indication of a problem.

Over time, the water heater can be prone to the build-up of sediments, which is a result of hard water. This can minimize the functionality of the heater, especially when it comes to heating. To prevent such problem, flushing is necessary. As much as possible, you have to flush it once or twice a year. For the right way to do it, follow the steps briefly mentioned below:

  1. For your safety, turn off the water heater before you start working on it. Start by rotating the gas cutoff counterclockwise and turn off the unit.
  2. Remove the cover of the heater. In some cases, you will need a screwdriver to take out the screws. You should also turn off the lever to stop the supply of water in the heater.
  3. Connect a hose to the end of the water inlet and the other end to a submersible pump. Once the hose is connected, position the submersible pump in a bucket with a capacity of at least five gallons.
  4. At this point, make a connection using the second hose. Connect to the hot water service port. The other end, on the other hand, must be placed in the bucket.
  5. Fill the gallon with undiluted, virgin white vinegar. Do not over-fill.
  6. Open the hot and cold ports of the water heater. Turn on the pump. At this point, the white vinegar will circulate and work its magic to get rid of the build-up of sediments.
  7. Leave it for about 45 minutes to an hour. Turn the pump off and drain the vinegar.
  8. Remove the screen filter from the water heater. You can have it cleaned or replaced depending on its current condition. Return the filter to its original position.
  9. Remove the hose and return the cover. Turn on the supply of water and gas. At this point, your gas tankless water heater should be good.


With the discussions above about the best gas tankless water heater that you can purchase, I hope that it is now a lot easier for you to decide which one to buy. All of the three options are exceptional, but you have to take a closer look at each of them to find one that will be most suitable for your needs and preferences.

Out of the three models, the one from Rheem is my personal favorite. Without a doubt, it has a high price tag, which may make some people ditch the idea of buying it. Nonetheless, this can be justified by the fact that it has a large heating capacity, making it ideal for large homes. It is also built to last and has an abundance of safety features.

On the other hand, if money is a major concern, the one from Takagi will be a reasonable alternative. It is significantly cheaper, but the performance is still commendable. This is the ideal choice if you have a small house with one to two showers, depending on the climate from where you are living.

Lastly, the Rinnai model comes with a mid-range price and is ideal for average-sized homes. The best thing about it is perhaps the fact that it is approved for mobile use, such as for trailers. However, it should be noted that the installation should only be done indoors, which should not be a problem given its compact profile.

Here are the best tankless water heater on the market today!

  • EcoSmart ECO 27 Electric Tankless Water Heater
  • Stiebel Eltron Tempra Plus Tankless Water Heater
  • Rheem RTEX-13 240V Heating Chamber Residential Tankless Water Heater
  • Rinnai V65IN 6.6 GPM Indoor Low NOx Tankless Natural Gas Water Heater
  • Eccotemp FVI-12-LP High Capacity Propane Tankless Water Heater
  • Rheem RTGH-95DVLN Direct Vent Tankless Water Heater
  • Takagi T-KJR2-IN-NG Gas Tankless Water Heater

If you want more information on water heaters, read our article: Best Tankless Water Heater Reviews

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